A large percentage of industrial cutting tools used to drill, cut, grind, and mill metals are made of tungsten carbide particles held together by a cobalt bonding agent. In a few instances the bonding agent may be nickel or platinum. The drilling, cutting, milling, or other metal working step requires the application of a liquid coolant or lubricant at the area of contact between the metal surface being machined and the drilling, cutting or milling tool. Although water or mineral oil can be used alone as a coolant or lubricant the practice has been to add compounds which increase the lubricity and cooling ability of the liquid and which delay its deterioration. These added compounds often, however, contain sequestering (chelating) agents and moities such as sulfur, chlorine, carboxyl groups and hydroxyl ions. It has been observed that when cutting, drilling or milling tools which are made up of tungsten carbide particles bonded with cobalt or nickel metal are exposed to these cutting fluids containing chelating agents or moities such as sulfur, chlorine, carboxyl groups and hydroxyl ions, the cobalt or nickel is leached away. Leaching of the cobalt or nickel metrix from the tool leaves a residue of carbide particles and results in premature failure of the tool. The presence of sequesterants or moities in the coolant or lubricant, as well as the mere presence of hydrogen and hydroxyl ions in a water-base cutting fluid, are thought to be responsible for the leaching of cobalt (or nickel). An object of this invention, therefore, is to reduce the corrosion of cobalt and nickel surfaces. Another object of this invention is to prevent or reduce the rate of leaching of cobalt and nickel binder from machining tools made up of abrasive particles such as tungsten carbide and a binder material such as cobalt or nickel.
Another object of this invention is to prevent or reduce the corrosion or oxidation of aluminum alloys during the said machining action when water-base coolants and lubricants are used.